BEIJING â€” As Kim Jong-un, the young leader of North Korea, consolidates his grip on power, China is showing signs of increasing frustration at the bellicose behavior of its longtime ally.
Since succeeding his father, Kim Jong-il, six months ago, Mr. Kim has quickly alienated the Obama administration and put North Korea on track to develop a nuclear warhead that could hit the United States within a few years, Chinese and Western analysts say.

Most surprising, though, is how Mr. Kim has thumbed his nose at China, whose economic largess keeps the government afloat. For example, shortly after Mr. Kim took over, a Chinese vice minister of foreign affairs, Fu Ying, visited Pyongyang, North Koreaâ€™s capital, and sternly warned him not to proceed with a ballistic missile test. The new leader went ahead anyway.

Now, the Obama administration and the Chinese government, who warily consult each other on North Korea, are waiting to see if Mr. Kim will follow in his fatherâ€™s footsteps and carry out a nuclear test, which would be North Koreaâ€™s third. The previous tests were in 2006 and 2009.

This month, the North Korean news agency said there were no plans for a third test â€œat present,â€ a statement analysts said suggested Mr. Kim was just waiting for a moment that better suited him.

â€œWe have made this absolutely clear to them; we are against any provocation,â€ Cui Tiankai, another Chinese vice minister of foreign affairs, said in a recent interview when asked about a possible third nuclear test by North Korea. â€œWe have told them in a very direct way, time and again, we are against it.â€ ................